The present invention relates to a slide guide unit for supporting a slider with high accuracy and a surveying instrument using the slide guide unit.
In a precision machine which requires a highly accurate positioning, for instance, a surveying instrument, a high accuracy of several seconds is required for setting a tilt angle. For instance, in a laser surveying instrument which projects a laser beam for measurement and performs an angle measurement and a distance measurement, a tilt of a laser luminescence device which projects a laser beam needs to be set in a unit of several seconds.
As a mechanism for setting the tilt of the laser luminescence device, there is a mechanism which tilts the laser luminescence device by giving a linear displacement to an arm extending from the laser luminescence device and converts the linear displacement into a tilt angle of the laser luminescence device.
In the tilt setting mechanism as described above, a slider as linearly movably supported is coupled with the laser luminescence device and a displacement is given to the slider by an actuator such as a motor or the like.
In order to perform an angle setting with high accuracy, the slider needs to accurately follow the displacement given by the actuator. However, when there is a looseness between the slider and a slider support portion which supports the slider, the displacement given by the actuator is not accurately transmitted to the slider and an error occurs.
It is to be noted that Japanese Patent Application Publication No. 2009-122012 discloses a mechanism for setting a tilt of a laser luminescence device.